Homemade Heavy Duty Telescope Mount

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The two telescope mounts and the wedge under the C-11 fork mount shown here were entirely fabricated from scrap steel rescued from the scrap iron dumpster at the truck dealership where I work. The five major materials used were 6- and 3-inch square pipe, 2-inch round pipe, 1/2-inch steel plate, and 10-inch truck frame channel. Various length 3/8-inch and 1/2-inch coarse-thread bolts and nuts were used as well as 5/8-inch coarse- and fine-thread all-thread rod. All angle brackets, either 90-degree or 30-degree, were cut from truck frame channel. The height of the two mounts was determined by the fact that the 6-inch square pipe was already cut to the dimentions used. Once I realized there was sufficient 3-inch square pipe to make legs for two mounts, I decided to make both of them. My thinking was to use the higher mount with my Schmidt camera at my observatory while using the shorter mount with a C-8 at home from my driveway. Casters were installed on the short mount to wheel it out of my garage. I practice however, I will swap the casters to the higher mount and use the shorter mount at the observatory because it is easier to sit and guide beside the shorter mount.

Wedge rear
The C-11 fork mount used to carry my Schmidt camera rests on a fabricated wedge fashioned from 10-inch truck frame channel and 1/2-inch steel plate. The two latitude adjuster jackscrews which raise or lower the elevation of the polar axis are 5/8-inch fine-thread all-thread rod cut from air brake chamber push rods used on an 18-wheeler. The attach points where the pivots are bolted together are held with self-locking bolts so they can be snugged tight with no play, but still be loose enough for the latitude adjuster to move when the jackscrews are turned.
Wedge back
A lower view showing the wedge and latitude ajusting jackscrews. The 33 amp-hour gel cell battery rests loosely in the channel iron behind the wedge upright and powers the C-11 drive base and supplies power to dew control heaters on the Schmidt camera and its guide scope.
Wedge side
Another view showing how the wedge upright and the jackscrew mounts can pivot as the jackscrews are turned to change the latitude adjustment.

Small mount
The 6-inch square pipe pier is further stabilized by three stripod-like legs made from 2-inch pipe which brace the pier against the ends of the base legs. The east and west base legs are two feet long while the north leg is three feet loog. This is to offset the weight shift from the overhaginging fork mount. Casters have been added to the ends of the base legs so the mount can be rolled out of the garage. Each base leg attaches to the mounting ring at the base of the pier with two 3/8-inch bolts.
Large mount
The higher mount has the same two- and three-foot base legs as the shorter mount, but the pier's taller height makes the stabilizing legs more vertical. Originally, both mounts were built with turnbuckles to tention between the top of the pier and ends of the base legs to stabilize the pier. However, this arangement made the pier vibrate longer than without the turnbuckels. The tripod-like braces which push down against the base legs were then designed to overcome this harmonic. The vibration rate is now less with the stabilizes than without them. To further reduce vibration to near zero, both piers were filled with dry sand through an access cover bolted near the top of each pier.
Both mounts
My wife, Mary, (5 foot 8 inches) stands by both mounts to show how big they are. The small mount is mounted on casters while the big mount is temporarily resting on furniture rollers in order to move it.

Top of pier
The top of each stabilizer has a protruding 5/8-inch bolt which has been sharpened to a "pencil point". The point inserts into a 3/8-inch hole drilled into the backet attached to the top of the pier. The bottom of the stabilizer has an extendable5/8-inch jackscrew (picture below) which is also pointed to engage another 3/8-inch hole in the bracket at the end of the base leg. When the jackscrew is extended by hand, it exerts a considerable force between the top of the pier and end of the base leg. When all three jackscrews are extended equally, the pier is very stable.
Jackscrew
When the telescope is in use, the entire mount is raised up off its casters with jackscrews at the end of the base legs. A 9/16-inch hut is welded to the top of the jackscrew so a wrachet and socket can quickly extend the jackscrew to support the weight of the mount.

Future Improvements

The design of these two telescope mounts evolved "on the fly" and they are still considered a work in progress. There is room for design improvement if future mounts are constructed. Two things I would do if another one is assembled are:
1) Cap the ends of the base legs. Although they are perfectly functional as is, for better aesthetics, I would plate over the open ends of the base legs.
2) Fill the vertical stabilizers with sand to further reduce vibration. Once filled with sand, a plug would have to be driven into the two-inch pipe from the jackscrew end to keep sand from fouling the threads of the extendable jackscrew. Once plugged, then the jackscrew mechanism would be welded to the end of the pipe.


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